Future gravity missions and quasi-steady ocean circulation

The quasi-permanent sea surface slope, i.e. the signature of oceanic currents that does not vanish when dynamic topography observations are averaged over a long period of time, will be resolved up to spatial scales of about 100 km by the GOCE space gravity mission. However, estimates of the quasi-permanent ocean dynamic topography, derived qualitatively either from models or from observations, indicate that some non-negligible residual signal remains below 100 km in areas of strong surface currents like the core of the Gulf Stream. One therefore expects that future missions can improve our knowledge of the ocean circulation in these areas. However, the potential improvements are small compared to the improvements expected from GOCE itself.